2002 Tiger (Panthera Tigris) SSP Annual Report
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AZA Annual Report of the Tiger SSP: 2002 TIGER (Panthera tigris) Species Coordinator/Amur Tiger Coordinator: Ronald Tilson, Minnesota Zoo Sumatran Tiger Coordinator/North American Studbook Keeper: Gerald Brady, Potter Park Zoo Indochinese Tiger Coordinator: Mike Dulaney, Cincinnati Zoo, North American Amur Tiger/Indochinese Tiger Studbook Keeper: Kathy Traylor-Holzer, Minnesota Zoo Introduction Three of five Panthera tigris subspecies (P.t. altaica, P.t. corbetti, and P.t. sumatrae) are currently managed by the AZA Tiger SSP, as recommended by the IUCN/SSC CBSG Tiger Global Conservation Strategy (GCS) and ratified at the 1992 Annual AZA Tiger SSP Meeting in Toronto. The Amur (Siberian) tiger population will be managed at the current level of 150 tigers, and each of the other two subspecies, Sumatran and Indochinese, will be expanded up to a maximum of 150 tigers each. All subspecies will be managed to maximize the retention of gene diversity, but it is recognized that it may not be feasible to maintain 90% gene diversity over a 100-year program without substantial founder importation, particularly for the Sumatran and Indochinese subspecies. For future years the Tiger SSP may need to consider the option of managing only two subspecies, one temperate (Amur) and one tropical (Sumatran or Indochinese), depending on our ability to reach program goals and the feasibility of acquiring sufficient founders. Data Tables (current through 1 March 2002) Two years One year Current Amur (Siberian) ago ago year # participating institutions 59 55 57 Total captive population 81.67 (148) 78.69 (147) 78.71 (149) # SSP animals managed 97 93 103 # SSP recommended births 12 12 15 # SSP non-recommended births 2 0 0 # deaths of SSP animals 14 12 13 # imports 0 1 0 # exports 0 0 0 # founders with descendants 57 57 57 Two years One year Current Sumatran ago ago year # participating institutions 30 28 27 Total captive population 33.26 (59) 33.26 (59) 31.24 (55) # SSP animals managed 55 48 47 # SSP recommended births 7 4 1 # SSP non-recommended births 0 0 0 # deaths of SSP animals 2 4 5 # imports 0 0 0 # exports 0 0 0 # founders with descendants 16 16 16 Two years One year Current Indochinese ago ago year # participating institutions 8 10 14 Total captive population 12.14 (26) 16.17 (33) 18.19 (37) # SSP animals managed 26 32 36 # SSP recommended births 14 9 6 # SSP non-recommended births 0 0 0 # deaths of SSP animals 0 2 2 # imports 2 0 0 # exports 0 0 0 # founders with descendants 4 4 4 1 Current Population Status The Tiger SSP currently manages three tiger subspecies – the Amur tiger (Panthera tigris altaica), Sumatran tiger (P.t. sumatrae) and Indochinese tiger (P.t. corbetti). As of March 2002 there are 87 SSP member institutions holding 266 tigers: 149 Amur tigers (56%); 55 Sumatran tigers (21%); 37 Indochinese tigers (14%); and about 25 generic tigers (9%). For the present, the Tiger SSP plans to expand the captive tiger population to eventually fill the 450 spaces suggested by the AZA Felid Taxon Advisory Group, allotting 150 spaces to each subspecies. The Amur tiger population will be held stable at approximately 150 tigers, while the Sumatran and Indochinese tiger populations will be expanded The current Amur tiger SSP population stands at 149 individuals derived from 57 founders and retaining 96.7% gene diversity. This captive population has a stable age structure and good reproductive success. Wild Amur tigers are found primarily in two populations in the Russian Far East and at least one or more populations on the Russia-China border and into northeast China. Estimates are about 400 wild adult tigers. This subspecies is considered critically endangered by the IUCN/SSC Cat Specialist Group and, like all five tiger subspecies, is threatened primarily by habitat loss and fragmentation. Poaching pressure apparently has declined recently due to intensive anti-poaching activities. The Sumatran tiger SSP population consists of 55 individuals derived from 16 founders and retaining 91.3% gene diversity. A breeding moratorium was under effect from 1994-1997 pending the results of DNA testing to verify subspecies purity, resulting in a gap in the population’s age structure. Importations of Sumatran tigers from Indonesia are being pursued to promote the genetic basis of this population. There are an estimated 400 wild Sumatran tigers living primarily within six national parks and possibly within a few other protected areas of Sumatra. This subspecies is also considered critically endangered by the IUCN/SSC Cat Specialist Group. In the past year field reports suggest that available habitat is under severe pressure from squatters and lumber extraction, fragmentation is increasing and poaching pressure is at an all-time high. The Indochinese tiger SSP population is now at 37 tigers maintained in 14 institutions. This population is based upon only four founders and currently retains 80.8% gene diversity. The importation of new founders is critical to the viability of this program and needs to be actively pursued. Wild Indochinese tigers live in small isolated subpopulations throughout mainland Southeast Asia and are estimated to number about 1,200-1,800. Indochinese tigers are considered endangered by the IUCN/SSC Cat Specialist Group. Many of these populations are fragmented, poaching is intense, and optimal habitat is decreasing. A recent field report from Cambodia describes a newly discovered population inhabiting a vast relatively undisturbed forest. Demographic Trends The Amur tiger population has been managed at about 150-160 animals over the past 15 years to allow newly available spaces to be used for the other two tiger subspecies. Generation time for this stable population is 8.2 years, sex ratios at birth are equal, and the average litter size is 2.5 cubs. Mortality prior to reproductive age is about 40%. The Sumatran tiger population has been fairly static at 55-60 since the breeding moratorium despite the resumption of breeding in 1997. This population is becoming demographically insecure as the majority of the breeders age. Post-moratorium recruitment has been low. Concerted efforts are being made to increase reproductive success so that the population can be expanded and made demographically viable. The Indochinese tiger population has grown dramatically from 10 to 37 individuals since population expansion was sanctioned at the 1998 master plan meeting, resulting in a young age structure. Demographic parameters for Sumatran and Indochinese tigers are similar to those for Amur tigers, except that mean litter size is larger (3.0 cubs) and generation time is shorter (5.8 years) for Indochinese tigers. Population Genetics Gene drop analyses of the Amur managed population indicate that 96.7% of the gene diversity has been retained in the population, representing 15.22 founder genome equivalents (FGE) from 57 founders. Gene diversity has gradually increased for the past 20 years due to population management and the periodic incorporation of new genetic founders from Europe and Russia. Current inbreeding levels are relatively low (mean F = 0.008). Genetic analyses of the Sumatran population indicates that 91.3% of the gene diversity has been retained. Sixteen founders (5.74 FGE) are represented in the population. Inbreeding is becoming more prevalent (mean F = 0.035), and new founders will be needed to maintain 90% gene diversity. The Indochinese tiger population has retained 80.8% gene diversity (FGE = 2 2.68) and is descended from four founders. All potential breeders are now related, and inbreeding will quickly increase from its current level (mean F = 0.079) without genetic supplementation. Recruitment of new founder stock for the Sumatran and Indochinese tiger programs is a high priority and will be essential for the viability of these SSP populations. Special Concerns New founders are necessary for the Sumatran and Indochinese tiger SSP populations. Acquisition of new founders, particularly from range country programs, is a great concern if these populations are to be viable. The availability of wild-caught problem tigers and/or their captive-born offspring is being investigated. A second concern is the relationship between the Tiger SSP and the private sector, where many tigers (mostly of unknown origin) are kept. During the 2002 Tiger SSP master plan meeting in Portland there was a discussion of the appropriateness of handling tigers in public places by AZA zoos. There was complete consensus of all members in attendance that such actions place the viewing public at risk of injury or death, that there is no education message of value being delivered, that such actions promote private ownership and a false sense of safe handling of exotic big cats, and that the animal itself loses its dignity as an ambassador from the wild. As a result, the committee resolved such actions were inappropriate for AZA-accredited zoos, and that the AZA accreditation committee should make compliance of this restriction part of its accreditation process. This opinion statement was conveyed to the executive committee of the Felid TAG for comments and action. Research The SSP continues to support research efforts to develop more reliable assisted reproduction techniques for tigers and other large cats. Field research continues in Sumatra to develop a holistic approach to the conservation of tigers across the island (see below). A seven-month field census of wild South China tigers was completed this year. Progress toward Goals 1. The Tiger SSP held a master plan meeting on 27-28 October 2000 at the St. Louis Zoo. Fourteen management group members, coordinators, advisors and institutional representatives attended the meeting. Twenty-six breeding recommendations and 27 transfers were scheduled for the 2001 management season. The Tiger SSP Five-Year Plan was briefly reviewed and updated during the meeting 2.